A voice mail system with improved detection and cancellation

(19)

(11)

EP 0 319 282 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	17.04.1991 Bulletin 1991/16

(43)	Date of publication A2:
	07.06.1989 Bulletin 1989/23

(21)	Application number: 88311363.1

(22)	Date of filing: 30.11.1988

(51)	International Patent Classification (IPC)⁴: H04M 3/50

(84)	Designated Contracting States:
	AT BE CH DE ES FR GB GR IT LI LU NL SE

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Priority:

01.12.1987 US 127338

(71)	Applicant: Cobotyx Corporation, Inc.
	Danbury, CT 06810 (US)

(72)	Inventors:
	O'Brien, Dennis J. West Linn, Oregon 97068 (US) Hanson, Paul G. Portland, Oregon 97219 (US) Klarquist, Thomas D. Oregon 97005 (US) Nepple, Bruce C. Portland, Oregon 97129 (US) Park, Michael C. Portland, Oregon 97219 (US) Rosas, Robin R. Oregon 97006 (US)

(74)	Representative: Meddle, Alan Leonard
	FORRESTER & BOEHMERT Franz-Joseph-Strasse 38 80801 München 80801 München (DE)

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References cited: :

(54)	A voice mail system with improved detection and cancellation

(57) A voice mail system (10) includes method and apparatus for muting a previously recorded audio signal upon detection of a DTMF signal to differentiate between recorded DTMF signals and valid DTMF commands. A DTMF signal detected after muting is recognized as an invalid command. The system (10) also includes method and apparatus for matching the impedance of a 2-to-4 wire converter (94) within the system (10) against the impedance of the outside telephone system (14) to improve the ability of the system (10) to detect the DTMF commands generated by a caller. Other features of the voice mail system (10) comprise apparatus for detecting the end of a message by recognizing call progress tones. The system also includes a message board in which each user of the system (10) can check its status and whether the user has a waiting message.

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